1. Field of the Invention
The present invention relates to image processing apparatus and method having a function to discriminate a characteristic of an input image, especially a character/line image area, a dot area and the like.
2. Related Background Art
Conventionally, in a case where an original in which characters and dot images are mixed is copied by a copy machine or the like, an input signal from a scanner unit is subjected to various processes and then output. For example, a character portion is intended to be sharply output, input image data is subjected to a filtering process to apply sharpness to that portion. However, if a dot image portion is subjected to the filtering process in the same manner, moire occurs on that portion. Therefore, such the copy machine is structured to provide plural copy modes such as a mode attaching importance to character reproducibility, a mode attaching importance to dot image reproducibility and the like, and to perform the filtering process according to each copy mode.
In a color copy machine, there is a type in which a character area and a dot image area are separated in the unit predetermined block, and the filtering process is changed over according to the separated area.
However, in the above color copy machine, even if an achromatic color image is read by a scanner, color aberration occurs due to mechanical vibration, chromatic aberration of a lens, difference in MTF and the like. Thus, there is a problem that an edge portion of an achromatic color is output as a chromatic color portion, or the like, thereby causing deterioration in image quality.
Especially, it is difficult to discriminate the dot area and the character area from each other. Thus, there are problems that the dot is edge-emphasized by erroneously discriminating the dot area as the character area, the character is smoothed by erroneously discriminating the character area as the dot area contrarily, and the like.
Further, since the image area separation performed in the conventional color copy machine is based on the discrimination in the unit of block, the erroneous discrimination between the dot image portion and the character image portion also happens in the unit of block, thereby causing deterioration in image quality.
Furthermore, a number of memories and process blocks are necessary to perform such a conventional image area separating process, thereby causing cost increase of the copy machine itself.
Therefore, an object of the present invention is to effectively and accurately detect a characteristic of an image.
Especially, an object of the present invention is to successfully discriminate a dot area and a character image area from each other.
A further object of the present invention is to provide a new function.
In order to achieve the above objects, in one preferred embodiment of the present invention, there is provided an image processing apparatus for extracting an image portion of a predetermined attribute from among an image including plural image portions respectively having different attributes, the apparatus comprising: a calculating means for calculating an isolated amount of a pixel value in each of plural areas respectively having different sizes; an integrating means for integrating the calculated isolated amount in a predetermined area; and an extracting means for extracting the image portion of the predetermined attribute according to the integrated isolated amount.